Heretofore the procedure of accumulating nuclear fuel rods into fuel bundle groups has been a manual operation. From various rod trays containing different types of fuel rods, operators pick out the number of each rod type specified for a particular fuel bundle and place them in a tray assigned to that bundle. This bundle tray is then removed for transport to a bundle assembly site where the fuel rods are removed and arranged in specified positions in fuel bundle assembly. The fuel rods are approximately 0.5 inches in diameter and may range in length from 5 to 14 feet. The longest fuel rods can weight up to 10 pounds. Current fuel bundle designs typically call for sixty fuel rods of as many as thirteen different rods types. Further designs will call for a greater number of rods of even more different rod types per bundle.
It is thus seen that manual accumulation of fuel rods in successive bundle trays is highly labor intensive and time-consuming. If a particular bundle is to include thirteen different types of fuel rods, the operators must pick varying numbers of fuel rods from at least thirteen rod trays and deposit them in one bundle tray. When the full complement of fuel rods has been accumulated in this bundle tray, it is removed to the bundle assembly site, and the process is repeated for the next bundle tray. While the operators are typically guided by a computerized accounting and tracking system, the tedious nature of the accumulation process leads to mistakes which then have to be corrected at the bundle assembly site. Moreover, the manual picking and placing of rods from tray to tray can inflict surface blemishes on the rods, which are potential sites for corrosion when subjected to a reactor environment.